Professional sports, as opposed to amateur sports, are sports in which athletes receive payment for their performance. Professional athleticism has come to the fore through a combination of developments. Mass media and increased leisure have brought larger audiences, so that sports organizations or teams can command large incomes.[1] As a result, more sportspeople can afford to make athleticism their primary career, devoting the training time necessary to increase skills, physical condition, and experience to modern levels of achievement.[1] This proficiency has also helped boost the popularity of sports.[1]

Most sports played professionally also have amateur players far outnumbering the professionals.

Baseball originated before the American Civil War (1861-1865). A humble game played on sandlots in particular, scoring and record-keeping gave baseball gravity. "Today," notes John Thorn in The Baseball Encyclopedia, "baseball without records is inconceivable."

In 1871 the first professional baseball league was created.[2] By the beginning of the 20th century, most large cities in the eastern United States had a professional baseball team. The teams were divided into two leagues, the National and American leagues. During the regular season, a team played only against other teams within its league. The most victorious team in each league was said to have won the "pennant;" the two pennant winners met after the end of the regular season in the World Series. The winner of at least four games (out of a possible seven) was the champion for that year. This arrangement still holds today, although the leagues are now subdivided and pennants are decided in post-season playoff series between the winners of each division.[2]

Baseball became popular in the 1920s, when Babe Ruth led the New York Yankees to several World Series titles and became a national hero on the strength of his home runs (balls that cannot be played because they have been hit out of the field). One of the most noteworthy players was the Brooklyn Dodgers' Jackie Robinson, who became the first African-American player in the major leagues in 1947. Prior to Robinson, black players had been restricted to the Negro League.[2]

Starting in the 1950s, major league baseball expanded its geographical range. Western cities got teams, either by luring them to move from eastern cities or by forming expansion teams with players made available by established teams. Until the 1970s, because of strict contracts, the owners of baseball teams also virtually owned the players; since then, the rules have changed so that players can become free agents, within certain limits, to sell their services to any team. The results have been bidding wars and stars who are paid millions of dollars a year. Disputes between the players' union and the owners have at times halted baseball for months at a time.[2]

Japan has also seen a prominent professional baseball circuit develop known as Nippon Professional Baseball, which was founded in 1934 and emerged as an international force after World War II. NPB is considered to be the highest caliber of baseball outside of the U.S. major leagues, and the best Japanese talent can emigrate to the U.S. by way of the posting system. Other prominent countries to play the game include South Korea (where their league has its own posting system with Major League Baseball), Mexico, Latin America, and the Caribbean states.

The game of American football was professionalized in the 1890s as a slow, and initially covert, process; William Heffelfinger and Ben "Sport" Donnelly were the first to secretly accept payment for playing the game in 1892.[citation needed] Regional leagues in Chicago, Pennsylvania, Ohio and New York had coalesced in the 1900s and 1910s, most of which gave way to the first truly national football league, the American Professional Football Association, in 1920.[citation needed] By 1920, pro football remained overshadowed by the college game. The first game involving an APFA team took place on September 26, 1920, at Douglas Park in Rock Island, Illinois, as the hometown Independents flattened the St. Paul Ideals 48-0. The first head-to-head battles in the league occurred one week later as Dayton topped Columbus 14-0 and Rock Island pasted Muncie 45-0.

Forward passes were rare, coaching from the sidelines was prohibited and players competed on both offense and defense. Money was so tight that Hals carried equipment, wrote press releases, sold tickets, taped ankles, played and coached for the Decatur club. As opposed to today’s standard 16-game schedule, clubs in 1920 scheduled their own opponents and could play non league and even college squads that counted toward their records. With no established guidelines, the number of games played—and the quality of opponents scheduled—by APFA teams varied, and the league did not maintain official standings.[3]

The Buffalo All-Americans, Chicago Tigers, Columbus Panhandles and Detroit Heralds joined the league before the end of the season, raising the total number of teams to 14, but the inaugural season was a struggle. Games received little attention from the fans—and even less from the press. According to Robert W. Peterson’s book "Pigskin: The Early Years of Pro Football," APFA games averaged crowds of 4,241. The association bylaws called for teams to pay a $100 entry fee, but no one ever did. Muncie played only one game before dropping out before the end of the season, which concluded on December 19.

At the conclusion of the season there were no playoffs (that innovation, although New York's regional league had used it, would not arrive until 1933) and it took more than four months before the league even bothered to crown a champion. Much as college football did for decades, the APFA determined its victor by ballot. On April 30, 1921, team representatives voted the Akron Pros, who completed the season undefeated with eight wins and three ties while yielding only a total of seven points, the champion in spite of protests by the one-loss teams in Decatur and Buffalo, who each had tied Akron and had more wins. The victors received a silver loving cup donated by sporting goods company Brunswick-Balke-Collender. While players were not given diamond-encrusted rings, they did receive golden fobs in the shape of a football inscribed with the words "World Champions."

Forgotten in the collective sports memory that the league’s official record books listed the 1920 championship as undecided until the 2013. The whereabouts of the Brunswick-Balke-Collender Cup, only given out that one time, are unknown. The legacy of two APFA franchises continues on, however. The Racine Cardinals now play in Arizona, and the Decatur Staleys moved to Chicago in 1921 and changed their name to the Bears the following year. Ten APFA players along with Carr are enshrined in the Pro Football Hall of Fame, which opened its doors in 1963 not far from the Canton automobile dealership that gave birth to the NFL in 1920.[4]

The APFA, by 1922 known as the National Football League, has remained the predominant professional football league in the United States, and, effectively, the entire world. The evolution from a haphazard collection of teams in big and small cities to the much more rigid structure it is in the present was gradual; the smaller markets were squeezed out in the late 1920s and early 1930s, a championship game was established in 1933, a draft was established in 1936, and schedules were standardized in the 1930s. A competing league has historically arisen to attempt to challenge the NFL's dominance every 10 to 15 years, but none managed to maintain long-term operations independent of the NFL and only two—the All-America Football Conference of the late 1940s and the American Football League of the 1960s—were strong enough to successfully compete against the league before the NFL subsumed their operations. Minor league football, although their leagues' memberships were unstable, began to arise in the late 1930s and remained viable as a business model up into the 1970s.

A major factor in the NFL's rise to dominance was its embrace of television early in the sport's history. As college football heavily restricted the rights of its teams to broadcast games (a policy eventually ruled to be illegal in 1984), the NFL instead allowed games to be televised nationwide, except in a team's home city; the restriction was softened in the early 1970s, by which point the NFL had secured broadcast deals with all of the major television networks, another major factor in the inability of any competing league to gain traction since then.

The related sport of Canadian football was eventually professionalized by the 1950s, which saw the evolution of the Canadian Football League. The CFL, despite losing all games in a series of contests against the NFL, was considered to be at least comparable in talent to the American leagues of the 1960s (its lone game against an AFL squad was a victory). Because Canada has a tenth of the population of the United States, the ability to make money from television was much lower, and although some of the cities of Canada were comparable to the major markets of the U.S., teams in places such as Saskatchewan and Hamilton were in markets quite small compared to even the small markets of the NFL, thus the CFL now pays noticeably less than other major professional leagues, but still more than enough to be considered fully professional.

The rise of indoor American football beginning in the late 1980s has allowed for smaller-scale professional football to be viable.

Ice hockey was first professionalized in Pittsburgh, Pennsylvania in the early 1900s (decade). As Canadians made up the vast majority of hockey players, early American professional leagues imported almost all of their talent before Canadian leagues began to form in the wake of a mining boom, depriving the U.S. leagues and teams of talent. Two distinct circuits formed: the Pacific Coast Hockey Association in western Canada and the northwestern U.S., and the National Hockey Association of central Canada, both of which competed for the then-independent Stanley Cup. The NHA's teams reorganized as the National Hockey League in 1917, and the West Coast circuit died out by the mid-1920s.

The NHL expanded to the United States in the 1920s, focusing on the northeastern and midwestern states. By the mid-1930s, the league had been set into six markets: Boston, New York City, Chicago and Detroit in the U.S., and Toronto and Montreal in Canada. These Original Six cities would be the only cities with NHL franchises from 1935 to 1967. During this time, the NHL was both stagnant and restrictive in its policies, giving teams territorial advantages, having teams with multiple owners in the same family (thus allowing the best players to be stacked onto certain teams), and restricting its players' salaries through reserve clauses. This stagnation allowed other leagues to arise: the Western Hockey League soon became the de facto major league of the western states and provinces, and the second-tier American Hockey League emerged in a number of midwestern markets the NHL had neglected, in addition to a handful of small towns.

Amid pressure from television networks that were threatening to offer the WHL a contract, the NHL doubled in size in 1967, beginning a period of expansion that lasted through much of the 1970s. The last major challenger to the NHL's dominance was the World Hockey Association, which successfully broke the NHL's reserve clause in court, drove up professional hockey salaries, and continued to pressure the older league into expansion. The WHA merged four of its remaining teams into the NHL in 1979, but had to give up most of its players, as they were still under NHL contract and had to return to their original teams. The NHL made its last pronounced realignment in the 1990s, moving most of the WHA teams out of their markets and establishing a number of new teams in the southern United States.

In Europe, the introduction of professionalism varied widely, and the highest-caliber league on the continent, the Soviet Championship League (proven to be at least equal to or better than the NHL in the 1970s), was officially composed of semi-professionalworks teams paid for their association with industries or government agencies (the Red Army squad employed members of the armed forces, and the Soviet Union often drafted the best hockey players in the country to serve on the squad). The modern-day descendant of the Soviet league, the Kontinental Hockey League, is fully professional and has a number of teams outside of Russia, to the point where it has the resources to sign NHL veterans. Other European countries such as Germany, Sweden, Switzerland, Norway, Finland, and Austria also have prominent professional leagues.

Professional basketball has the advantages of much smaller rosters than other professional sports, allowing the sport to be viable in smaller cities than other sports. Professional basketball leagues of varying caliber can be found around the world, especially in Europe and South America.

Professional athleticism is seen as a contradiction of the central ethos of sport, competition performed for its own sake and pure enjoyment, rather than as a means of earning a living.[1] Consequently, many organisations and commentators have resisted the growth of professional athleticism, saying that it was so incredible that it has impeded the development of sport. For example, rugby union was for many years a part-time sport engaged in by amateurs, and English cricket has allegedly suffered in quality because of a "non-professional" approach.[1] An important reason why professional sports has been resisted in history was that organisations for professional sports usually did not submit to the international sports federations, and could have their own rules.[citation needed] For example, the National Basketball Association was formerly not a member of the FIBA.

Men involved in professional sports can earn a great deal of money at the highest levels. For instance, the highest-paid team in professional baseball is New York Yankees.[5]Tiger Woods is the highest paid athlete totaling $127,902,706 including his endorsement income,[6] which massively exceeds what he earns from tournament golf. Woods recently became the world's first athlete to earn a billion dollars from prize money and endorsements.[7] It would have taken the salary of 2,000 1980s professional golfers each making $58,500 to match up with Tiger Woods’ current salary. Samuel Eto'o is the world's second highest earning athlete and the highest paid footballer in the world, raking in £35.7 million (over $54 million) a year excluding off-field earnings.[8] The top ten tennis players make about $3 million a year on average. Much of the growth in income for sports and athletes has come from broadcasting rights; for example, the most recent television contract for the NFL is valued at nearly US$5 billion per year.[9] Women in the U.S., on the other hand, make much less, for example as of 2014, the WNBA enforced a maximum salary of US$107,000 for star players (coaches could earn double that).[10] This is largely driven by the fact that the American viewing audience has far less interest in women's professional sport compared to men's; average in-person attendance and television viewership are both far higher for the NBA compared to the WNBA. According to investopedia.com, a male star like Kobe Bryant or LeBron James can individually earn a salary larger than every player in the WNBA combined.[11]

Outside of the highest leagues, however, the money professional athletes can earn drops dramatically, as fan bases are generally smaller and television revenues are nonexistent. For instance, while the National Football League's teams can afford to pay their players millions of dollars each year and still maintain a significant profit, the second-highest American football league in the United States, the United Football League, has consistently struggled to pay its bills and has continually lost money despite allotting its players only US$20,000 a year.[12][13][14] In the United States and Canada, most lower-end professional leagues run themselves as affiliated farm teams, effectively agreeing to develop younger players for eventual play in the major leagues in exchange for subsidizing those players' salaries; this is known as the minor league system and is most prevalent in professional baseball and professional ice hockey. Otherwise, the league may be required to classify itself as semi-professional, in other words, able to pay their players a small sum, but not enough to cover the player's basic costs of living.

Many professional athletes experience financial difficulties soon after retiring, due to a combination of bad investments, careless spending, and a lack of non-athletic skills. In the United States, some of these problems are mitigated by the fact that the college sports system ensures most professional athletes receive a college education with no student debt, a legacy that provides them with a career path after their sports career ends; the wear and tear of a career in pro sport, in contrast, can cause physical and mental side effects (such as chronic traumatic encephalopathy, a condition that has seen a massive rise in public awareness in the 2010s) that can harm a former professional athlete's employability.

The average salary of a player in the Chinese Super League was about ¥10.7 million (£1 million) for the 2011 season, up from ¥600,000 in the 2010 season. The highest paid player for the 2011 Chinese Super League season was Dario Conca of Guangzhou Evergrande who received an annual salary of ¥66.4 million ($10.5 million) after income tax, putting him among the highest paid players in the world.[17]

The highest paid player for the 2011-2012 Russian Premier League season was Samuel Eto'o of Anzhi Makhachkala, who at the end of the 2011-12 season was expected to receive a total salary of RUB 900.2 million (£35.7 million) after income tax, making Eto'o the second highest earning athlete in the world and the highest paid footballer in the world followed by Lionel Messi and Zlatan Ibrahimović.[8][18][19]

The average salary of a player in the German Bundesliga was about €3.3 million (£2.5 million) for the 2010-2011 season, up from €2.5 million in the 2009-2010 Bundesliga season.[20] The highest paid player for the 2010-2011 Bundesliga season was Franck Ribéry of Bayern Munich who received a salary of €6.3 million after income tax.[21]

In the Italian top league, Serie A, the average salary was about €5 million for the 2010-2011 Serie A season, up from €1 million in the 2005-2006 Serie A season.[22] The highest paid player for the 2010-2011 Serie A season was Zlatan Ibrahimović of A.C. Milan who received a salary of €25.9 million after income tax and which also includes Ibrahimović's bonuses and endorsements.[23]

The average salary of a player in the English Premier League was about £1.2 million in the 2007-2008 Premier League season, up from £676,000 in 2006-2007 Premier League season. Top players such as John Terry and Steven Gerrard can make up to £7 million per year with the players of Premier League club Manchester City F.C. receiving an average salary of £7 million for the 2010-2011 Premier League season, up from £5.5 million in the 2009-2010 Premier League season.[25][26] Players in lower divisions make significantly less money. In 2006-2007 season the average salary of a player in the Championship (the second tier of the English football pyramid) made £195,750 while the average salary for Football League and League Two (tier 4) was £49,600.[25]

The highest salary in Major League Soccer in 2015 was the $7.2 million paid to Kaká, who plays for the newly formed Orlando City SC.[27] Kaká was signed as a beneficiary of MLS' Designated Player Rule, which was instituted in 2007 for the express purpose of attracting international stars. Now-retired English star David Beckham was the first player signed under its provisions.[28] When the rule was instituted, each team had one "Designated Player" slot with a salary cap charge of $400,000, but no limit on actual salary paid.[28] Since then, the number of Designated Players per team has increased to three, with each counting for $387,500 of cap room in 2014.[29] The league's average salary is about $283,000 per year, but the median salary is closer to $110,000.[30] MLS' minimum player salary will increase in 2016 from $60,000 to $62,500 for most players, and roster players #25-28 will see their minimum salary increase from $50,000 to $51,500.[31][32]

In 1970, the average salary in Major League Baseball in the U.S. and Canada was $20,000 ($123,342 inflation-adjusted). By 2005, the average salary had increased to $2,632,655 ($3,228,355 inflation-adjusted) and the minimum salary was $316,000 (adjusted: $387,502).[33] In 2012 the average MLB salary was $3,440,000, the median salary was $1,075,000, and the minimum salary had grown to four times the inflation-adjusted average salary in 1970 ($480,000).[34]